The M88 engine was used in the original Motorsport
car, the M1. The M88 was based on
the M49 engine used in the BMW 3.0CSi.
BMW engineers used a 4-valve head and a two-row chain.
The cylinder head was made in two parts. The lower part formed the
combustion chambers and water jackets, and the upper half contained the
camshaft bearings and the bores for the tappets.
Kugelfischer fuel injection was used with individual throttle
and the distinctive six inlet pipes. The M88 produced 277 bhp in
the version built from 1978 to 1981 for the BMW M1.
Procar M1's, the M88 was tuned to
470 to 490 bhp. The resulting M88/1 engine had new camshafts, bigger
valves, reshaped ports, forged pistons, use of throttle slides (instead of
butterfly valves), and improved exhaust.
For Group 5 racing, the engine
was pushed to between 850 and 900 bhp by the addition of two exhaust-gas
turbochargers. This was the M88/2 powerplant.
From 1985 to 1987 the M88 was
used in the 5 Series M5 Sedan and
from 1983 to 1989 in the 6 Series
M635CSi Coupe. The engine was designated M88/3 and produced 286 bhp.